Dental Tool and Guidance Devices

ABSTRACT

The present invention is directed to a system of devices and a method for preparing a tooth to receive a restoration. The system includes a dental instrument for removal of portions of a tooth in the mouth of a patent and an overlay for guiding the dental instrument during the step of tooth removal. The overlay is designed for temporary installation into the mouth of the patient to guide the dental instrument to remove tooth material. The overlay has one or more sets of guide walls, with a predetermined configuration capable of contacting one or more guide projections of the dental instrument, and a receptacle capable of receiving and attaching to the dental instrument.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 14/119,666 filed Mar. 13, 2014, published as U.S. PatentApplication Publication No. 2014/0248577 A1, which is a national phaseentry under 35 U.S.C. § 371 of International Application No.PCT/US2012/039569 filed May 25, 2012, published as InternationalPublication No. WO 2012/162605 A2, which claims the benefit of thefiling date of U.S. Provisional Application No. 61/490,361, filed May26, 2011, entitled Dental Tool and Guidance Devices, all of which arehereby incorporated herein by reference.

FIELD OF THE TECHNOLOGY

The present invention relates to devices and methods for preparing teethfor tooth restorations, and in particular it relates to systems, devicesand methods for teeth to receive previously produced tooth restorations.

BACKGROUND OF THE INVENTION

Complete, intact teeth that are cosmetically desirable, that wear evenlyand provide a balanced bite are the objectives of patients. Over time,however, problems arise in teeth due to accidents, deterioration fromwear and tear, decay, tooth movement, etc. As a result, teeth may becomeaccidentally chipped or cracked from a variety of causes includingnormal wear and tear, and weakened from decay due to the mouth hygieneand care practices and/or by consumption of certain foods such assweets, use of tobacco, disease, medications, certain congenitalconditions, and environmental effects. To this end, dental practitionersand their patients have relied on a variety of methods to repair thesedeformities and weaknesses of the teeth.

The repair of teeth often requires preparation and modification of theexterior shape and size of a tooth to be able to receive variousprostheses or restorations such as crowns, inlays, onlays, bridges, andveneers. Also, to prepare the appropriate prosthesis or restoration,either impressions or 3-dimensional scanning must be conducted of theoriginal unmodified tooth and the modified tooth. Dental practitionersoften place a temporary prosthesis over the modified or prepared toothwhile a permanent prosthesis is manufactured, but the use of such atemporary device and the removal of any cement used to place thetemporary device over the prepared tooth may create a discrepancybetween the prepared tooth and the internal configuration of theprosthesis.

A need has existed in the art to develop a system for more efficientlyand reliably treating the teeth of patients for receiving restorationsand other prosthesis.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, a system, methods and productshave been discovered which provide a simpler, more reliable and moreconvenient technique for treating a tooth in need of a restoration part,in view of decay, cracks or other maladies existing in the tooth. Thereis provided a system of dental devices that may be used to modify atooth by limiting the removal of tooth material to produce a shape orconfiguration that mates with or corresponds to the interiorconfiguration of a restoration part. This system makes it possible toprepare a restoration part in advance of the preparation of the tooth.Also, the tooth can be accurately prepared with the configuration thatcorresponds to and mates with the internal configuration of therestoration part. By following this technique, the restoration part isavailable to be installed immediately after the preparation of thetooth. Therefore, in a single office visit, it is possible for thedentist to prepare the tooth and mount the restoration part onto theprepared tooth.

Under both of these conventional methods and the present invention,there is first a diagnosis indicating the need to treat a tooth with arestoration part. Normally, this is based on initial x-rays or otherdiagnostic techniques that identify the location and extent of decay,cracks or other maladies of the tooth. A mold, cast, impression, orthree-dimensional data must be created based on the original tooth to betreated. At this point the present invention departs from conventionaltechniques in practice. Conventional techniques require the tooth to berevised and reshaped to remove decay, cracks and other maladies to leavea prepared tooth for receiving a restoration part. After tooth materialhas been removed, the revised configuration of the prepared tooth mustbe defined from a second mold or cast or three-dimensional data. Theprepared, revised tooth is normally fitted with a temporary crown, toprotect the prepared tooth and provide some comfort for the patientuntil the restoration part is manufactured, which can take days toweeks. Both sets of casts/molds or data are used, usually at an off-sitelaboratory, to prepare the restoration. The original tooth configurationis the basis for preparing the exterior of the restoration part whilethe prepared, revised tooth configuration is the reverse or negative forthe configuration of the interior of the restoration part.

The procedure of the present invention reduces inconveniences topatients such as eliminating some office visits and eliminating the needfor wearing a temporary crown. Therefore, under the present inventionthere is no need to prepare the tooth prior to producing the restorationpart. There is also no need to produce a cast, mold or three-dimensionaldata for the prepared tooth prior to installing the restoration part.There is no need for a temporary crown to be installed over the preparedtooth, nor the removal of the temporary crown and associated cementwhich can create complications with the fit of the restoration part.Such complications can require further revision of the tooth to fit therestoration or further modification of the restoration part. Alsoeliminated is the discomfort to the patient in wearing a temporarydevice and the greater risk of infection while the prepared tooth isexposed or is under the temporary crown.

In accordance with the present invention, a system of devices has beendiscovered for use in the treatment of a tooth to remove certainpredetermined portions of the structure of the tooth. The systemcomprises:

-   -   (i) a dental instrument for removal of portions of a tooth in        the mouth of a patient, said dental instrument adapted to be        utilized with an overlay that is installed over or near the        tooth to be treated; and    -   (ii) an overlay for temporary installation into the mouth of a        patient to guide a dental instrument in the removal of tooth        structure of the treated tooth, said overlay including a cutting        guide utilized with an appropriate dental instrument to limit        the movement of the dental instrument during operation to        restrict tooth structure removal to the predetermined portion of        the tooth, said cutting guide comprising one or more of the        following: (a) one or more sets of guide walls, wherein the        adjacent guide walls in each set and their surfaces have a        predetermined configuration capable of contacting one or more        guide projections of a dental instrument to limit the movement        of the dental instrument and restrict tooth structure removal to        the predetermined portion of the tooth; and (b) a receptacle        hingedly or slidedly connected to the overlay and capable of        receiving and attaching to the dental instrument, wherein the        dental instrument when attached to the receptacle, has limited        movement with respect to the tooth to be treated and which        restricts tooth structure removal to the predetermined portion        of the treated tooth.

With respect to the dental instrument, it comprises: a tooth treatmentassembly for removing a portion of tooth structure; and one or moreguide projections extending from the instrument in the direction of theworking tooth to be treated when the instrument is in position for toothstructure removal, said one or more guide projections being capable ofcontacting a cutting guide in an overlay device installed in thevicinity of the tooth to be treated to limit the three-dimensionalmovement of the tooth treatment instrument with respect to the workingtooth.

The dental overlay can include the cutting guide as described above orcan include other embodiments of the cutting guide in which a receptacleis used for attaching the dental instrument to the overlay where thereceptacle is hingedly or slidedly attached to the overlay. When thedental instrument is attached to such a receptacle of the overlay,because the movement of the receptacle is specially limited, themovement of the dental instrument is also limited which restricts itsability to remove tooth structure from the treated tooth to thepredetermined portion of the treated tooth.

In another embodiment of the invention a method is provided for treatinga working tooth in a patient's mouth by removing portions of itsstructure, said method comprising the steps of:

-   -   determining the three-dimensional structure of the working tooth        to be removed for treatment;    -   providing the dental instrument comprising a tooth cutting        element for removal of a portion of a tooth's structure and one        or more guide projections extending from the instrument in the        direction of the tooth to be treated when said tooth treatment        element is in operating position for tooth structure removal;    -   preparing a dental overlay having a cutting guide with a        configuration that is capable of contacting one or more guide        projections of the dental instrument to limit the movement of        the dental instrument to restrict the structure removed from the        tooth under treatment to the predetermined three-dimensional        portions of tooth structure for the treatment.

These and other embodiments and further details of the invention areelsewhere described in the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with respect tonon-limiting drawings illustrating some preferred embodiments of theinvention. In the drawings:

FIG. 1 is a perspective view showing a dental instrument placed in anoverlay for use by a dentist in removing tooth structure in accordancewith the present invention.

FIG. 2 is a perspective view showing a hand grip and a tooth treatmentassembly of the dental instrument of FIG. 1.

FIGS. 3A and 3B are perspective views of two configurations the toothtreatment assembly and a projection head of the dental instrument shownin FIG. 1.

FIGS. 4A and 4B are plan views of two configurations of the projectionhead and the tooth treatment assembly shown in FIGS. 2 and 3.

FIG. 5 is a perspective view of a dental overlay placed on a patient'steeth for use by a dentist in removing tooth structure in accordancewith the present invention.

FIG. 6 is a plan view of the dental overlay shown in FIG. 5.

FIG. 7 is a bottom view of the dental overlay shown in FIG. 5.

FIG. 8 is a perspective view of an alternative arrangement of an overlayplaced on a patient's teeth for use by a dentist in removing toothstructure in accordance with the present invention.

FIG. 9 is a perspective view of a further alternative arrangement of anoverlay placed on a patient's teeth for use by a dentist in removingtooth structure in accordance with the present invention.

FIG. 10 is a perspective view of a still further alternative arrangementof an overlay placed on a patient's teeth for use by a dentist inremoving tooth structure in accordance with the present invention.

FIG. 11 is a perspective view of an overlay device for use by a dentistin removing tooth structure in accordance with the present invention.

FIG. 12 is a plan view of the overlay device shown in FIG. 11 placed ona patient's teeth for use by a dentist in removing tooth structure.

FIG. 13 is a bottom view of the overlay device shown in FIG. 11.

FIG. 14 is a perspective view of an overlay device placed on a patient'steeth for use by a dentist in removing tooth structure in accordancewith the present invention.

FIG. 15 is a perspective view of a tooth prior to any preparation of thetooth.

FIG. 16 is a perspective view of the tooth shown in FIG. 15 afterpreparation of the tooth using the dental instrument of FIG. 1 incombination with the dental overlay of FIG. 5 in accordance with thepresent invention.

Within the drawings, the same or similar reference numeral is used tocorrespond to the same or an analogous element.

DETAILED DESCRIPTION

In the Brief Summary of the Invention above and in the DetailedDescription of the invention herein, and the claims below, and in theaccompanying drawings, reference is made to particular features (e.g.,method steps) of the invention. It is understood that the inventionembraces and includes all possible combinations of the featuresdescribed in the text, in addition to those depicted in the drawings.For example, where a particular feature is disclosed in the context of aparticular aspect, arrangement, or embodiment of the invention, or aparticular claim, that feature can also be used, to the extent possible,in combination with and/or in the context of other particular aspects,arrangements, and embodiments of the invention, and in the inventiongenerally.

The term “comprises” and grammatical equivalents thereof are used hereinto mean that other components, ingredients, steps, etc. are optionallypresent. For example, an article “comprising” (or “which comprises”)components A, B, and C can consist of (i.e., contain only) components A,B, and C, or can consist not only of components A, B, and C but also oneor more other components.

Where reference is made herein to a method comprising two or moredefined steps, the defined steps can be carried out in any order orsimultaneously (except where the context excludes that possibility), andthe method can include one or more other steps which are carried outbefore any of the defined steps, between two of the defined steps, orafter all the defined steps (except where the context excludes thatpossibility). The term “step of” does not mean “step for”.

The terms “lower,” “upper,” etc. and derived directional terms such as“horizontal”, “vertical”, “upward”, and “downward” are based on a normalconfiguration of an overlay as shown in the drawings, wherein theoverlay fits onto the lower teeth of a patient with their rootsextending vertically downward. The term dentist in this text is not beinterpreted restrictively and can also be read as dental practitioner,dental technician, dental assistant, dental auxiliary, dental therapist,dental designer, etc.

The present invention provides for a system for use by a dentalpractitioner (“dentist”) in precisely preparing, revising, or modifyinga working tooth for receipt of a preformed restoration such as an inlay,onlay, crown, bridge, or veneer. Such a system has two main components:(i) a dental instrument having features capable of contacting a suitableguiding configuration of an overlay or overlay device and (ii) anoverlay or overlay device which can be attached to a working toothand/or neighboring teeth and configured to limit the three-dimensionalmovement of a dental instrument, thereby limiting the movement of thedental instrument itself with respect to the tooth being treated. Amethod of use of the system is further provided in accordance with thepresent invention.

According to conventional techniques, a diagnostic evaluation of a toothreveals an existing condition requiring the tooth to be treated byinstallation of a restoration or prosthesis. Under these conventionalapproaches, the tooth to be treated is revised and prepared first, andthen its revised configuration is used to fabricate the internalconfiguration of the restoration. Therefore the restoration isfabricated to fit the already prepared tooth.

According to the invention, the system comprising the overlay with acutting guide and the dental instrument which coordinates with theoverlay enables the tooth to be prepared after fabrication of therestoration, where the prepared tooth conforms to the configuration ofthe existing restoration.

The dentist can prepare a cast or mold of the existing working tooth inthe context of neighboring teeth and can identify by x-ray and/or otherdiagnostic techniques the portions of the working tooth that should beremoved, due to e.g., decay, cracks, weaknesses, deterioration,impediment to bite, etc. Based on this information, the inventionprovides for producing a restoration part, in advance of the physicalrevision of the tooth so that this restoration part is available to thedentist even before he or she starts physically preparing the tooth. Thetooth can then be prepared with precision by using the configuredoverlay to revise the tooth in a manner to correspond to or mate withthe interior of the restoration. The availability of the restorationmakes it possible to mount it directly onto the tooth in the same visitthat the tooth is prepared. This substantially reduces inconvenience ofthe patient and reduces the number of visits made to the dentist. Thisalso reduces the possibility of a prepared tooth becoming contaminatedduring the extended time period between tooth preparation andinstallation of the final restoration.

Referring now to the drawings, FIG. 1 shows a preferred embodiment of adental instrument 10 adapted to fit and to coordinate with an overlaydevice for use in removing portions of tooth structure pursuant to apredetermined configuration, to prepare a working tooth to receive apreformed restoration. In this embodiment, the dental instrument 10 hasa hand grip 30 attached to a tooth treatment assembly 50, including forexample a dental bur, that is installed within and encapsulated by aprojection head 20. As shown in FIG. 1, the tooth treatment assembly andthe projection head may be integrated with one another so as to form amonolithic structure described further herein.

As illustrated in FIG. 2, the hand grip 30 provides a portion of theinstrument 10 for resting in a human hand and has a shaft thatoptionally may be hollow along its longitudinal axis. One end of thehand grip 30 is attached to one side of a connecting end 31 which isattached on its other side to the tooth treatment assembly 50. The toothtreatment assembly 50 of FIG. 2 is used when the tooth treatmentassembly 50 does not form an integrated, monolithic structure with theprojection head 20. The tooth treatment assembly 50 includes a toothtreatment element 52, and appropriate pneumatic and/or mechanical driveswell-known in the art that run through the hand grip 30 and may includea housing 40. However, the housing 40 forms part of the projection head20 in the arrangement in which the tooth treatment assembly 50 andprojection head 20 are integrated. In this preferred embodiment, themechanical drives cause a rotation of a tooth treatment element 52 usedfor removing tooth structure. It is important to note that the toothtreatment element 52 need not be rotated to accomplish its intendedfunction of removing tooth structure from a working tooth 60, an exampleof which is shown in FIG. 15. For instance, it may cut through a workingtooth in a sawing or milling action. The instrument can also be adaptedfor a tooth treatment element that removes tooth material by laser orother techniques.

As shown in FIGS. 2-4, the projection head 20 surrounding the toothtreatment assembly 50 preferably has a bottom base 23 from which a sidewall 27 extends upwardly and around the periphery thereof leaving anopening 29 on one end. The opening 29 is large enough to accommodate thethickness of the connecting end 31 of the hand grip 30. In the two-piecearrangement of the tooth treatment assembly 50 and the projection head20, an interior face 28 of the side wall 27 of the projection head 20preferably wraps around the periphery of the bottom base 23 such that aportion of the side wall 27 approximately conforms to the shape of thehousing 40 of the tooth treatment assembly 50. In either arrangement, atool aperture 24 extends through the thickness of the bottom base 23 andhas a shape and size to enable it to accommodate the tooth treatmentassembly 50 and to allow water jets or air streams from the toothtreatment 50 assembly to pass through to the working tooth 60. In thepreferred embodiment, guide projections 21 extend downwardly from aprojection flange 26 that protrudes, often in a horizontal directionaway from the bottom base 23 as shown in FIGS. 1 and 3, from the bottombase 23. Alternatively, one or more of these projections 21 could alsoextend from the bottom base 23 itself. In another alternativearrangement, the projection flange 26 could protrude from a combinationof the bottom base 23 as well as the side wall 27.

The guide projections 21 are capable of contacting physical limits, suchas those defined by guide surfaces, of a suitable guiding configurationof a predetermined overlay device. In this manner, the suitable guidingconfiguration can limit the lateral movement of the tooth treatmentassembly 50 and corresponding tooth treatment element 52 with respect tothe tooth being prepared.

The guiding configuration provides a corresponding limitation on themovement of the entire dental instrument 10 by the user and thus canremove predetermined portions of tooth structure such that when movementof the dental instrument 10 throughout the guiding configuration iscomplete, the resulting prepared tooth 70, an example of which is shownin FIG. 15, will have dimensions that enable it to be fitted to andmated with the interior of a preformed restoration.

In one embodiment, the projection head 20 is capable of resting on asuitable guiding configuration. Within this configuration, the bottombase 23 of the projection head 20 preferably may have a flat bottomsurface 25 as shown in FIG. 3 or a curved surface (not shown), but otherarrangements of this surface are within the scope of the presentinvention. The guide projections 21 extending from the projection head20 in this configuration preferably have a predetermined length tocorrespond with the guiding configuration of the overlay device. In thismanner, the guide projections 21 will preferably have a length such thateach of their ends or extremities 22 do not contact a surface of thesuitable guiding configuration when the projection head 20 rests upon asuitable guiding configuration. Because the projection head 20 restsupon the suitable guiding configuration in this arrangement, the guidingconfiguration limits the movement of the projection head 20 towards theguiding configuration and thus controls the depth of the projection head20 and thus the tooth treatment assembly 50 and ultimately the depth ofpenetration of the tooth treatment element 52 into a working tooth 60.

Alternatively, the guide projections 21 may have a predetermined lengthsuch that each of their ends 22 does contact a surface of the suitableguiding configuration. In this manner, the guiding configuration limitsthe movement of the guide projections 21 towards the guidingconfiguration and accordingly controls the depth of the projection head20 and ultimately the depth of penetration of the tooth treatmentelement 52 into a working tooth. In such an arrangement, the projectionhead 20 may but need not rest upon the guiding configuration.

In some cases, a suitable guiding configuration used in conjunction withthe preferred embodiment of the dental instrument 10 may have variousspacings amongst its elements. The projection head 20 may be selectedwith a size and shape that enable it to fit within only preselected orcertain of these spacings. For instance, a set of adjacent guidesurfaces extending from the base of a suitable guiding configuration mayhave stepped, or a series of, spacings between guide surfaces, wherebyonly some of the adjacent guide surfaces will be sufficiently spaced toenable the projection head 20 of the dental instrument to fit.

In another embodiment of the invention, an overlay may be adapted toreceive or accommodate a dental instrument, such as the dentalinstrument 10 previously described herein. FIGS. 5-12 show preferredconfigurations of such an overlay. In the preferred configurations shownin FIGS. 5-7, an overlay 90 has a predetermined base 80. This base 80has an open area 81 that extends through the thickness of the base 80and exposes surfaces of the working tooth 60 or adjacent teeth 65 atleast larger than the portions of the tooth structure to be removed.Furthermore, as illustrated in FIG. 7, the base 80 has tooth contactingsurfaces 82 that are contoured to provide contact regions capable ofcontacting one or more teeth to secure the overlay 90 in a suitableposition for the predetermined overlay configuration to be used inremoving the predetermined portions of tooth structure from the tooth 60being treated. In this regard, the tooth contacting surfaces 82 may havea shape that substantially corresponds to the outer shape of portions ofthe working tooth and/or teeth adjacent to the working tooth.

In this arrangement, a first guide wall 86 and a second guide wall 87which form a first set of guide walls extend vertically from one side ofthe base 80. As shown in FIGS. 5 and 6, third and fourth guide walls 88,89 forming a second set of guide walls similarly extend vertically froman opposite side of the base 80. Although not shown in the figures, anoverlay may have additional sets of guide walls. Each set of guide wallsin the preferred embodiment shown in FIGS. 5 and 6 has first and secondguide surfaces 83, 84 on guide walls 86, 87, respectively. However, aset of guide walls may have more or less than two guide walls.

In the preferred embodiment shown in FIGS. 5 and 6, the first and secondguide walls 86, 87 are positioned distally along the base 80 whereas thethird and fourth guide walls 88, 89 are positioned mesially along thebase 80. However, a set of guide walls may be positioned on the buccalor facial and/or lingual or palatal sides of a comparable base 180, asillustrated in FIG. 8. In the preferred embodiment, the first and secondguide surfaces 83, 84 of respective guide walls 86, 87 are capable ofcontacting one or more guide projections of a dental instrument to limitthe movement of a tooth treatment element of a dental instrument, suchas tooth treatment element 52 of dental instrument 10. Preferably, guidesurfaces 83, 84 of each of respective guide walls 86, 87, in combinationwith base 80, define respective side apertures 95A, 95B and are spacedapart a sufficient distance to each receive such a guide projection. Asfurther shown, guide wall 86 of each set of guide walls 86, 87, incombination with base 80, define opposing side openings 96A, 96B and arespaced apart a sufficient distance to receive a tooth treatment elementof a dental instrument, such as tooth treatment element 52 of dentalinstrument 10.

In the preferred embodiment shown in FIGS. 5 and 6, the guide walls 86,87 have a substantially uniform thickness in a direction perpendicularto the base 80 lending to a substantially flat surface across the topsurface 85 of each of the guide walls 86, 87. Furthermore, guide walls86, 87 have a substantially equivalent predetermined height above thebase 80 which, when coupled with the substantially flat top surface 85,permits a portion of a dental instrument, such as the projection head 20of the dental instrument 10, to lay across the thickness of adjacentguide walls, often laying flat as in the arrangement shown in FIG. 1. Inthis manner, the predetermined height of guide walls 86, 87 can limitthe movement of a tooth treatment element, such as the tooth treatmentelement 52 of dental instrument 10, in the direction, which is often theapical direction, of the tooth. In an alternative arrangement, the topsurface of a set of guide walls may have a bevel, chamfer, round,indent, or have an alternative shape to allow an overlay to receive asurface of a dental instrument at a variety of angles.

Preferably, during the tooth preparation procedure the overlay 90 shouldremain fixed and not move once it is placed around the working tooth 60.Moreover, the overlay 90 should remain in a stable position even when adental instrument intended for use with the overlay 90, such as dentalinstrument 10, makes contact with it. The position of the overlay 90 canbe secured by contact of the contacting surfaces 82 of the overlay 90with tooth surfaces or by the use of a bonding agent, such as one thatis light cured or a temporary cement or by projections from the overlay90 that engage portions of a tooth, including the working tooth 60,either of the adjacent teeth 65, or dentition on the opposing jaw.

As in the preferred embodiments shown in FIGS. 5 and 6, the guide wallsmay be curved. In this arrangement, each guide wall within a set ofguide walls is substantially curved about the same axis.

In alternative arrangements of preferred embodiments, first and secondguide walls of a given set of guide walls may be substantially parallelto one another in a direction parallel to a plane through thelongitudinal center lines through the guide walls. For instance, inFIGS. 8 and 9, there are provided first and second guide walls 186, 187and 286, 287 configured in a manner to limit the movement of a toothtreatment element of a dental instrument in directions substantiallyparallel to and substantially perpendicular to the proximal surfaces ofeach working tooth, respectively. Each set of guide walls 186, 286 and187, 287 is capable of contacting one or more guide projections of adental instrument to limit the movement of a tooth treatment element ofa dental instrument, such as tooth treatment element 52 of dentalinstrument 10. Each set of guide walls 186, 286 and 187, 287, incombination with base 80A, define respective side apertures 195A, 195Bto receive such a guide projection. As further shown, guide wall 186 andguide wall 187, in combination with base 80A, define opposing sideopenings 196A, 196B each having a side opening width measured in a firstplane perpendicular to each set of guide walls 186, 286 and 187, 287sufficient to receive a tooth treatment element of a dental instrument,such as tooth treatment element 52 of dental instrument 10. As shown,the side opening width is larger than a side aperture width of each ofside apertures 195A, 195B measured in the first plane. In a furtheralternative arrangement, each guide wall within a given set of guidewalls is nonparallel to each other guide wall. In such an arrangement,the spaces between the guide walls of a given set of guide walls may bearranged in a circular pattern as shown in FIG. 10. Although not shownin the figures, the guide walls may also be in a rectangular,triangular, or a number of other configurations.

FIGS. 11-13 illustrate another preferred embodiment for a dentalinstrument for use in removing a portion of the structure of a workingtooth 60 in preparation for a subsequent restoration. The dentalinstrument includes a hand grip attached to a tooth treatment assembly,often through a connecting end. The tooth treatment assembly preferablyincludes a housing, a tooth treatment element, and appropriate pneumaticand/or mechanical drives as in the tooth treatment assembly 50.

The housing of the tooth treatment assembly is adapted to connect to,and preferably to fit within, a receptacle element portion of an overlaydevice, such as a receptacle 270 of an overlay 290 described furtherherein, and is further capable of interlocking with the receptacle. Inan alternative arrangement, the housing of the tooth treatment assemblymay have certain features for increased stability of the dentalinstrument. Such features may include a non-circular or asymmetriccross-section or interlocking grooves on the exterior capable ofinterfacing with an overlay device.

With reference to FIG. 11, the tooth treatment assembly of the dentalinstrument may be fixed to a receptacle element of the overlay such thatit is capable of moving in tandem with the receptacle. In one sucharrangement, the tooth treatment assembly may be integrally connected toa receptacle, such as the receptacle 270, such that it is capable ofpivoting about a hinge, such as a hinge 242, that connects thereceptacle to an overlay device, such as the overlay 290.

Again referring to FIG. 11, when the tooth treatment assembly isattached to a receptacle element connected to an overlay device, thetooth treatment element may protrude through the receptacle element andmay extend into an open area of the overlay device, such as the openarea 281, such that it is capable of contacting physical limits of asuitable guiding configuration provided by open area 281, of apredetermined overlay device to provide the tooth treatment element withsufficient access to a three-dimensional portion of the tooth to beremoved. In this manner, the suitable guiding configuration may act incoordination with the receptacle element to limit the lateral movementof the tooth treatment assembly and corresponding tooth treatmentelement with respect to the tooth 60 being prepared.

The guiding configuration and receptacle element thus provide acorresponding limitation on the movement of the entire dental instrumentby the user and thus the instrument can remove predetermined portions oftooth structure such that when movement of the dental instrumentthroughout the area through which the receptacle element permitsmovement within the guiding projection, the resulting prepared tooth 70,an example of which is shown in FIG. 16, will have dimensions thatenable it to be fitted to and mated with the interior of a preformedrestoration.

In the arrangement shown in FIG. 11 in which the tooth treatmentassembly is installed within a receptacle element attached to anoverlay, such as the receptacle 270, the overlay may restrain thevertical movement of the receptacle element to limit the movement of thetooth treatment assembly towards the guiding configuration and thusultimately control the depth of penetration of the tooth treatmentelement into the working tooth 60.

In another embodiment in accordance with the invention, an overlay 290may be adapted to receive or accommodate a dental instrument, such asthe dental instrument previously described herein. The overlay 290 has apredetermined base 280 that has an open area 281 that extends throughthe thickness of the base 280 and exposes surfaces of the working tooth60 or adjacent teeth 65 at least larger than the portions of the toothstructure to be removed as well as a receptacle 270 attached to the base280. Furthermore, as illustrated in FIG. 13, the base 280 has toothcontacting surfaces 282 that are contoured to provide contact regionscapable of contacting one or more teeth to secure the overlay 290 in asuitable position for the predetermined overlay configuration to be usedin removing the predetermined portions of tooth structure from the tooth60 being treated. In this regard, the tooth contacting surfaces 282 mayhave a shape that substantially corresponds to the outer shape ofportions of the working tooth and/or teeth adjacent to the workingtooth.

As shown in FIGS. 11 and 12, the receptacle 270 is a feature that isadapted to receive and may congruously surround a portion of a housingof a tooth treatment assembly, such as the housing of the toothtreatment assembly, when the housing is installed within the receptacle270. The receptacle 270 preferably has a bottom base 223 from which aside wall 227 extends upwardly and around the periphery thereof leavingan opening 229 on one end. The opening 229 is large enough toaccommodate the thickness of the connecting end of the hand grip. Acombination of the bottom base 223 and the side wall 227 form inner andouter surfaces 273, 274 of the receptacle. The inner surface 273 of thereceptacle 270 preferably conforms to the shape of a housing of thetooth treatment assembly, such as the housing of the tooth treatmentassembly. The receptacle 270 may further have a head locking featurethat is capable of engaging an undercut located on a housing of a toothtreatment assembly, such as the housing of the tooth treatment assembly,and a shaft locking feature that is capable of engaging an undercutlocated on a connecting end of a tooth treatment assembly, such as theconnecting end of the tooth treatment assembly. The outer surface 274 ofthe receptacle 270 preferably includes a flange 275 extending therefrom.In a preferred arrangement in which the receptacle 270 is circular toconform to a similarly circular tooth treatment assembly, the flange 275preferably extends circumferentially around the outer surface 274 of thereceptacle 270, as in the arrangement shown in FIGS. 11 and 12. A toolaperture 224 extends through the thickness of the bottom base 223 of thereceptacle 270 to enable a tooth treatment element as well as water jetsor air streams to pass through.

Again referring to FIG. 11, the receptacle 270 may be movably attachedto a base surface 284 of the overlay 290. In this manner, the receptacle270 may be pivotally attached to the overlay 290 through the hinge 242as shown in FIG. 11. In this manner, the receptacle 270 is capable ofrotating about the longitudinal axis of the hinge. Although the hinge242 is shown as a pin in FIG. 11, any type of a rotational connectionbetween the overlay and the receptacle, such as attaching the receptacleto a roller bearing on the overlay, is within the scope of thisinvention.

As FIG. 11 further illustrates, when a dental instrument is attached tothe overlay 290, a tooth treatment element of the tooth treatmentassembly of the instrument may protrude through the tool aperture 224and may extend into an open area 281 of the overlay 290 such that it iscapable of contacting physical limits of a suitable guidingconfiguration defined by open area 281 of the overlay 290. Thereceptacle 270 may also include at least one guide projection (notshown) extending towards the open area 281. In this manner the base 280is capable of coordinating with the hinge 242 and the open area 281 iscapable of contacting either or both of the tooth treatment element orthe guide projection to confine the movement of the receptacle 270 andthus the tooth treatment assembly to a predetermined three-dimensionalregion of the working tooth 60.

In an alternative arrangement, a receiving wall 260 is attached to thebase surface 284 of the overlay 290. The receiving wall 260 has a rim265 along its length. In a preferred arrangement, the receiving wall 260may have notches 261, but alternative arrangements may not have thesenotches. The receiving wall 260 is preferably placed at a distance awayfrom the hinge 242 such that, during rotation of the receptacle 270, theflange extending from the outer surface 274 of the receptacle 270 iscapable of being received within a region between the base surface 284and the rim 265 of the receiving wall 260. In this manner, the rim 265may urge the receptacle 270 towards the base surface 284 as thereceptacle 270 is rotated about the hinge.

In another alternative arrangement of this embodiment, as illustrated inFIG. 14, an overlay 390 may have tooth contacting surfaces forcontacting portions of tooth structure, an open area 381 that providesaccess to portions of teeth for removal of tooth structure, a first basesection 384, and a second base section 389.

Each of the first base section 384 and the second base section 389 mayinclude a base 383 and an extending portion 391 extending from the base383. The extending portion 391 of the first and the second base sections384, 389 may include an outer surface 386 facing in a direction oppositea working tooth 60 and an inner surface 387 facing in a directiontowards a working tooth 60 in which the outer and inner surfaces 386,387 are separated by a thickness 388. Each of the first and the secondbase sections 384, 389 additionally may include a slot 385 having alength and a width. A further slot 395 wider than the slot 385 isdefined adjacent to the slot 385 and between the inner surface 387 ofthe extending portion 391 and an inner base surface 392 of the base 383,as shown.

As shown in FIG. 14, a receptacle 370 may be attached to each of thefirst and the second base sections 384, 389 through the use of the slot385. As in the receptacle 270 disclosed previously herein, thereceptacle 370 includes a housing in which a main body of the housingmay congruously surround a portion of an assembly of a tooth treatmentassembly, such as the assembly housing 240 of the tooth treatmentassembly 250, when the assembly housing is installed within thereceptacle 370. The main body of the receptacle 370 preferably has abottom base 323 from which a side wall 327 extends upwardly and aroundthe periphery thereof leaving an opening 329 on one end. The opening 329is large enough to accommodate the thickness of the connecting end ofthe hand grip. A combination of the bottom base 323 and the side wall327 form inner and outer surfaces of the main body of the receptacle.The inner surface 373 of the receptacle 370 preferably conforms to theshape of an assembly of the tooth treatment assembly, such as theassembly housing 240 of the tooth treatment assembly 250. The receptacle370 may further have a head locking feature that is capable of engagingan undercut located on an assembly of a tooth treatment assembly, suchas the assembly housing 240 of the tooth treatment assembly 250, and ashaft locking feature that is capable of engaging an undercut located ona connecting end of a tooth treatment assembly, such as the connectingend of the tooth treatment assembly. A tool aperture 324 extends throughthe thickness of the bottom base 323 of the receptacle 370 to enable atooth treatment element, such as tooth treatment element 252, as well aswater jets or air streams to pass through.

The receptacle 370 may additionally include a guide plate 376 attachedthrough a connecting portion of the housing of the receptacle to thebottom base 323. The guide plate 376 has a width. In a preferredarrangement, the width of the guide plate 376 is greater than the widthof the slot 385 of the first base section 384. Further, the connectingportion preferably has a length substantially equal to the thickness ofthe slot 385 and thus the guide plate 376 is preferably located such adistance from the bottom base 323. In this manner, when the guide plate376 is inserted through the outer surface 386 and then the thickness ofthe slot 385 of the first base section 384, the guide plate 376 is heldsubstantially against the inner surface 387 and thus limits the movementof the receptacle 370 in the direction towards the working tooth 60.Further, when the connecting portion attached to the guide plate 376 isinserted within the slot 385, the connecting portion of the receptacle370 contacts the slot 385 to limit the lateral movement of thereceptacle 370 with respect to the working tooth 60 being treated. Sucha configuration thus limits the movement of a tooth treatment assemblyadapted to fit within the receptacle 370 and a corresponding toothtreatment element with respect to the working tooth 60 being prepared.

In each of the embodiments presented herein, the overlay 290, 390preferably should remain fixed and not move once it is placed around theworking tooth 60. Moreover, the overlay 290, 390 should remain in astable position even when a dental instrument intended for use with theoverlay 290, 390 makes contact with it. The position of the overlay 290,390 can be secured by contact of the contacting surfaces 282, 382 of theoverlay 290, 390 with tooth surfaces or by the use of a bonding agent,such as one that is light cured or a temporary cement or by projectionsfrom the overlay 290, 390 that engage portions of a tooth, including theworking tooth 60, either of the adjacent teeth 65, or dentition on theopposing jaw.

It may be possible to utilize the same configuration of an overlay, suchas the overlays 90, 290 described previously herein, made for one tooth,in the preparation of a tooth of the same or different patient, wheresuch other tooth has sufficiently similar dimensions, shape andcondition. Therefore, it is within the scope of this invention to havesome overlays prepared which can be standardized, reused and/orreproduced. Also, it is within the scope of this invention to utilizedata obtained in the preparation of prior overlays and restoration partsin the design and generation of new overlays having substantiallysimilar dimensions and shapes.

A dentist may use a dental instrument such as the dental instrument 10and an overlay configuration such as the overlay 90 previously describedto remove portions of the structure of a working tooth with precision.It is generally preferred to retain and utilize as much of a healthyworking tooth as practical. When a tooth is damaged or infected, thedamaged and/or infected parts of the tooth may have to be removed first,and the tooth may have to be reconstructed before preparing the toothfor further treatment with a restoration device. The preliminary repairor reconstruction of the tooth minimizes the chance that an infectiondevelops underneath a tooth restoration part. This also maximizes thelifetime of the tooth restoration part as the basis for the toothrestoration part, namely the working tooth, no longer contains defectiveor damaged portions.

Several methods are known for acquiring three-dimensional data from apatient's dentition to determine the portions of a tooth that should beremoved based on factors of decay and structural defects, as well asportions of tooth that should be retained intact to provide sufficientstrength in the ultimate preparation of a dental overlay configuration.Such data can be retrieved, for example, by processing and analyzingphotographs, x-rays or other information taken from the patient'sdentition or by directly obtaining such data from the patient throughthe use of intra-oral scanning devices. Another method is making aphysical impression of the dentition and then subsequently scanning thisimpression or a reversed cast of the impression. Such scanning can beconducted with a CAD/CAM 3D scanning device. Illustrative of such adevice is the Activity 101 Scanner from Smart Optics, DentalWings3-Series Scanner, or 3Shape 710 Scanner of Woburn, Mass., USA. Whilesuch a scanning device can scan a model of the dental arch with atolerance of about 10 μm this does not take into account other errorfactors obtained from the making of the impression and the casting ofthe dental impression. In preparing the ultimate restoration part ordental prosthesis, these other error factors or tolerances must beconsidered.

The CAD program can choose the specific configuration for the overlay,and ultimately the configuration for the prepared tooth by utilizingcertain protocols which are based on prior experience for preparingdental prostheses.

After acquiring the three-dimensional data, this data can be processedby a computer so as to determine a portion of tooth structure to beremoved from the tooth. The portion of the tooth to be removed will bedetermined in view of any further tooth treatment required. If aparticular shape of the prepared tooth is required for allowing furthertreatment, the portion for tooth structure removal will be chosen sothat after preparation of the tooth, this particular shape will remain.

Determining the portion for tooth structure removal depends on manyparameters and will differ from case to case. Parameters include thelocation of the tooth in the mouth of the patient, amount and locationof the damaged tooth structure, distance of the tooth to neighboringteeth, the bite of the patient, etc. In a preferred embodiment, thecomputer will also take into account the different parts of the toothsuch as the enamel, dentin, pulp, cementum, etc. in determining thepredetermined part. It is also understood within the general aspects ofthe invention that the patient's tooth may have to be built up throughconventional techniques and materials prior to the actual step ofpreparation of the tooth, utilizing the overlay or after preparation ifthe decay is exposed.

According to the invention, the computer is programmed to automaticallydetermine the predetermined part of tooth structure to be removed.However, also according to the invention, the computer can be programmedeither by manually selecting parameters or actually inputting code todetermine the portion for tooth structure removal subject to additionallimitations or parameters imposed by a practitioner. The practitioner'sinput can be included by visualizing data relating to the tooth onto acomputer display and allowing the practitioner to enter a parameterrelating to the preparation of the tooth. Preferably, a preview of thetooth is visualized onto the computer display together with a preview ofa simulation of the prepared tooth, so as to allow a practitioner to seethe impact of chosen parameters onto the prepared tooth. The latterfeature provides a larger degree of freedom to the dentist orpractitioner to benefit from advice from other practitioners. The methodfor producing a dentist tool according to the invention enables a lessexperienced dentist to benefit from computer-assisted recommendations aswell as other practitioners.

Next, the dental overlay is installed into the mouth of a patient in amanner to secure the overlay in a position to enable the overlay tolimit a dentist's movement of a tooth treatment element of a dentalinstrument. A dental instrument is then employed into the mouth of apatient by orienting it in a manner such that guide projectionsextending from the dental instrument are situated between the guidesurfaces of two or more guide walls that are arranged in a configurationfor contacting the guide projections.

In one embodiment, a bottom surface of a projection head on a dentalinstrument can rest on a top surface of the guide walls. In this manner,the predetermined height of the guide walls determines the depth ofpenetration of a tooth treatment element on a dental instrument. Whenthe top surfaces of the guide walls are substantially flat and a portionof a dental instrument such as a projection head is laid across thesetop surfaces, the dental instrument may be slid along these topsurfaces.

Finally, the dentist's instrument may be operated in conjunction withthe dental overlay. In this regard, when a tooth treatment element suchas a dental bur extends from a dentist's instrument, sliding thedentist's instrument along the top surfaces will produce a predetermineddepth or predetermined depths of cut within a prepared tooth 70, asshown in FIG. 10. Accordingly, the limitations of the guide surfaces ofthe guide walls in conjunction with the limits sets by the height of theguide walls upon a tooth treatment element of a dentist's instrumentdefine a three-dimensional region of the working tooth in which portionsof tooth structure are removed.

Although the invention herein has been described with reference toparticular embodiments, in both described and illustrated contexts, itis to be understood that these embodiments are merely illustrative ofthe principles and applications of the present invention. It istherefore to be understood that numerous modifications may be made tothe illustrative embodiments and that other arrangements may be devisedwithout departing from the spirit and scope of the present invention asdefined by the appended claims.

1-9. (canceled)
 10. A dental overlay device for temporary installationinto the mouth of a patient to limit movement of a dental instrumenthaving a tooth treatment element configured for removing a portion oftooth structure from a tooth in the removal of a predetermined portionof working tooth structure to be removed from a working tooth to betreated, the overlay device comprising: (i) a base having one or moresurfaces for contacting portions of one or more teeth in a patient tosecure the overlay device in a suitable position with respect to thetooth to be treated, and the base further having one or more open areasfor exposing the portion of the working tooth structure to be removed;and (ii) a cutting guide comprising a plurality of sets of adjacentguide walls and attached to the base, each of the sets of adjacent guidewalls defining a respective aperture configured for receipt of a guideprojection of separated guide projections of the dental instrument in adirection transverse to a longitudinal axis defined by a respective oneof the separated guide projections, a combination of one of the adjacentguide walls of each of the sets of adjacent guide walls defining anopening for receipt of the tooth treatment element between the guidewalls of the combination, wherein each of the adjacent guide walls ofeach of the sets of adjacent guide walls have a predeterminedconfiguration for contacting the respective one of the guide projectionsof the separated guide projections of the dental instrument to limit themovement of the tooth treatment element of the dental instrument andthereby restrict the portion of the working tooth structure to beremoved to the predetermined portion of the working tooth to be treated.11. The dental overlay device of claim 10, wherein the adjacent guidewalls have a predetermined height configured for limiting the movementof the tooth treatment element in the apical direction of the workingtooth.
 12. The dental overlay device of claim 10, wherein the adjacentguide walls within any one of the sets of adjacent guide walls includeopposing surfaces that are substantially parallel to each other.
 13. Thedental overlay device of claim 10, wherein the adjacent guide wallswithin any one of the sets of adjacent guide walls include opposingsurfaces that are curved about the same axis.
 14. The dental overlaydevice of claim 10, wherein the adjacent guide walls within a set ofadjacent guide walls are not parallel to each other.
 15. The dentaloverlay device of claim 10, wherein the overlay device is configured forlimiting the movement of the dental instrument in either one or both ofmesial and distal directions.
 16. (canceled)
 17. The dental overlaydevice of claim 10, wherein the overlay device is configured forpreparing the working tooth to receive a crown, an inlay, an onlay, abridge, or a veneer. 18-20. (canceled)
 21. The method of claim 39,further comprising: acquiring three-dimensional data for the workingtooth, the acquired three-dimensional data comprising exteriordimensions and interior structure of the working tooth; and processingthe three-dimensional data with a computer to define the portion of theworking tooth structure to be removed. 22-34. (canceled)
 35. The dentaloverlay device of claim 10, wherein the overlay device is configured forlimiting the movement of the dental instrument in either one or both ofbuccal and lingual directions.
 36. The dental overlay device of claim10, wherein the opening has a width in a plane defined by ends of theadjacent guide walls of the sets of adjacent guide walls, the widthbeing greater than respective widths of the apertures in the plane,wherein the adjacent guide walls of each of the sets of adjacent guidewalls have a predetermined configuration for contacting the guideprojections of the separated guide projections of the dental instrumentto limit the movement of the tooth treatment element of the dentalinstrument without the tooth treatment element contacting the adjacentguide walls of the cutting guide.
 37. The dental overlay device of claim10, wherein at least one guide wall of the sets of adjacent guide wallsextends over the one or more open areas.
 38. The dental overlay deviceof claim 10, further comprising a further opening for receipt of thetooth treatment element between the guide walls of the combination. 39.A dental system, comprising: the dental overlay device of claim 1; and adental instrument for use with the dental overlay device in guiding thedental instrument, the dental instrument comprising: a hand grip; atooth treatment assembly including the tooth treatment element; and theplurality of guide projections, wherein the plurality of guideprojections extend from the tooth treatment assembly, each of theplurality of guide projections being spaced from the tooth treatmentelement and being configured for receipt between and for contact withthe adjacent guide walls of one of the sets of adjacent guide walls ofthe cutting guide of the overlay device to thereby restrict the portionof the working tooth structure to be removed to the predeterminedportion of the working tooth to be treated.
 40. A method for treating aworking tooth to be treated in a patient's mouth by removing apredetermined portion of working tooth structure from the working tooth,the method comprising: receiving a plurality of guide projections of adental instrument through respective apertures in a first direction,each of the apertures being defined by and extending between ends ofadjacent guide walls of a plurality of sets of adjacent guide walls of afirst dental overlay device mounted on either one or both of the workingtooth or another tooth in the patient's mouth; receiving a toothtreatment element of the dental instrument defining a longitudinal axisthrough an opening in the first direction, the first direction beingtransverse to the longitudinal axis of the tooth treatment element, thetooth treatment element being configured for removal of tooth structureand the opening being defined by and extending between one of theadjacent guide walls of each of the sets of adjacent guide walls; andmoving the tooth treatment element towards the working tooth whilemaintaining the plurality of guide projections between the sets ofadjacent guide walls, the first dental overlay device being configuredto contact the plurality of guide projections of the dental instrumentto limit the movement of the tooth treatment element and therebyrestrict the portion of the working tooth structure to be removed fromthe working tooth to the predetermined portion of working toothstructure.
 41. The method of claim 40, further comprising mounting atooth contacting surface of the first dental overlay device on eitherone or both of the working tooth and the other tooth to secure the firstdental overlay device in a suitable position with respect to the workingtooth.
 42. The method of claim 40, wherein the opening has a width in aplane defined by ends of the adjacent guide walls of the sets ofadjacent guide walls, the width being greater than respective widths ofthe apertures in the plane.
 43. The method of claim 40, furthercomprising: receiving the plurality of guide projections of the dentalinstrument between respective sets of guide walls of a second dentaloverlay device mounted on one or both of the working tooth and the othertooth in the patient's mouth, the second dental overlay device beingconfigured differently than the first dental overlay device; moving thetooth treatment element towards the working tooth while maintaining theplurality of guide projections between the respective sets of guidewalls of the second dental overlay device, the second dental overlaydevice being configured to contact the plurality of guide projections ofthe dental instrument to limit the movement of the tooth treatmentelement and thereby restrict the portion of the working tooth structureto be removed from the working tooth to the predetermined portion ofworking tooth structure.
 44. The method of claim 40, further comprisingactivating the tooth treatment element for the removal of a portion ofthe working tooth.
 45. The method of claim 44, further comprising movingthe tooth treatment element through an open area of the first dentaloverlay device to remove at least part of the predetermined portion ofworking tooth structure to be removed.
 46. The method of claim 44,further comprising, during a same visit to a dental practitioner by thepatient as the receiving and moving steps were performed, fitting andmating a preformed restoration to remaining tooth structure of theworking tooth after removing the predetermined portion of the workingtooth structure from the working tooth.